Thermometric instrument for indicating the freshness of air in confined spaces



THERMOMETRIC INSTRUMENT FOR INDICATING 'THE FRESHNESS OF AIR m cownmsn SPACES.

R. H. DAVIS.

Mar. 13, 1923.

FILED SEPT.3,1921- Patented Mar. 13, 1923.

umT-Evvsma ROBERT HENRY avis, on ennon}, NGLAND,

,THERMOMETRICINSTRUMENT ma mmonrme r'nnsnnn'ss or A a-1a i CQNFINED SPACES. i f

Application-filed SeptemberB, 192i. SeriaINo-fi498365. i

To all whom it may concern: 7 Be it known that IyRonnnr dicating the Freshness of ,Air in Confined cation.

Thls invention relates to a thermometric instrument for indicating the freshnessof' air in confined spaces.

The usual dry-bulb thermometer, commonly employed for indicating the temper-' ature'of rooms and other closed spaces, does not register the effect on the human body of the movement of the air, the extent of which largely determines the degree of freshness of the atmosphere. The object of this invention is to provide an instrument or appliance by means of which an indication of the effect of the movement of the air upon the temperature of the body can be obtained.

An instrument, constructed according to the invention, and which I term a fresh air meter, comprises a dry-bulb thermometer, in combination with means for continuously supplying a constant quantity of heat to a jacket or the equivalent, enclosing the thermometer and exposed to the surrounding air. By this means the heat, which is imparted to the said jacket, is dissipated by radiation and by convection, the degree of' loss due to the latter being dependent upon the rate of movementiof the surrounding air. It will thus be seen that the temperature, indicated on the thermometer, is dependent upon the temperature and rate of motion of the air.

In a suitable construction of instrument, according to the invention, the thermometer is enclosed in a metal jacket, in which it is held centrally, out of contact with the walls thereof, the said jacket being in metallic connection with a metal case containing an electric lamp of given candle power. The heat generated in the lamp is conducted through the walls of the case, and the thermometer jacket, so as to heat the air within the latter, and thereby the thermometer bulb. The heat thus conducted to the thermometer jacket is partly radiated into the surrounding air, and partly carried away by convection, to an HENRY Dnvrsy a subject of the King of Great Britain, residing at 187 Westminster Bridge Road, London, England, have invented a new and useful Thermometric Instrument for Inextent dependent upon'the degree of movement' of the air. 1 In practice, the instrument is so constructed' and the thermometer so arranged, that'a given standard reading, or range of readings, indicates the cooling power of the air,"which is m'ost advantageous to health,

the comfort of the body, and efficiency in To enable the invention to be fully understood I will; describe by referenceto the accompanying drawing, which illustrates in vertical section an instrumentin accordance with the invention. I I Y a is the dry-bulb thermometer and I?) is the jacket surrounding the lower part thereof and'havin' its-exteriors'urface ex- 1 I posed to toe a r oi the confined space'the freshness of which air it isdesired to (lb-f tain an indication. The thermometer is supported within the jacket 6 at the upper part thereof by the bridge-piece c, the said bridge-piece having a central socket cl fit- "ting the thermometer tube the lower part of which is centered within the jacket by perforated discs or distance pieces 6. i is the metal case containing an electric lamp 9 of given candle power, with the upper part of which case the jacket I) is'in metallic connection, the latter being enlarged at the base to the same diameter as the said case 7. Or, any other suitable form'of heating appliance may be used. it indicates ventilating openings in the case f to prevent over-heating of the thermometer a. The thermometer jacket 6 is open at the top and is provided at its lower end preferably in. the enlarged portion with apertures, in-' dicated at b-b, which allow a circulation the walls of the case f and the jacket 6- so as to heat the air within the latter and thereby the thermometer bulb. A- portion of the heat thus conductedto the jacket 7) is partly radiated and partly carried away 7 still by enclosed Within a screen, the reading was over 40 C. An ordinary dry-bulb thermometer varied but little when screened, and, therefore, failed to show the discomfort and relaxing effect of the still air which the human body felt. It willthus be seenthat by arranging the heating and ventilation of factories, schools .and irooms and other closed spaces so as to maintain the reading ofthe fresh 2Ll1l[l3,t61 atrQO" to I 23 (1., cool, comfortable conditio ns,=suitable for healtlrand Work, willrbe obtained. Claims: i

1. An instrument for indicating xt-he freshness ofair in ,confinedspaces or compartments comprising a dry-bulb thermometer, a heat conducting, jacket enclosing the bulb .end thereof, said bulb "being ex posed'to the air of the compartment and means for continuously supplying a constant quantityof heat to the jacket, substantially as described.

2. An instrument for indicating the freshness of air in confined spaces or compartments comprisingadry bulb thermometer, ,a heat conducting jacket enclosing the bulb end part of the thermometer and providedwith apertures permitting the circulation of air from the said spaces or compartments though said jacket, a heat conducting case in contact with said jacket but out oi communication therewith, and a constant source ot'heat located in said heat con ducting case.

Aninstrumcnt for indicatingthe freshnessvof air in confined spaces or compartments comprising a heat conducting case provided with apertures, a vertically disposed heat conducting acket in contact with v saidicasebut separated thereform byan imperforate Wall, said acketbeingiprovided adjacent to its upper-anddower ends with apertures communicating With-the surround 

